We think this involves what Antonio Damasio has called an “as if body loop” mechanism.

Emotions can bypass the body and afford homeostatic comfort by simulating a felicitous body state as if it were occurring. Evidence for this “as if body loop” mechanism originates from research showing that individuals with right-hemisphere damage to the insula and somatosensory cortex perform poorly on emotion recognition tasks, presumably because their capacity to simulate in these damaged areas others’ observed body state is impaired. The same structures may provide the neural substrate for simulating a our own body state, particularly when, as suggested by Antonio Damasio and Hanna Damasio, this is a state that has already occurred in the organism.

Nostalgia, then, could be eminently suited to engage the “as if body loop” mechanism, given that it involves a recalled image of the self in a felicitous state.

Tim Wildschut is a senior lecturer in psychology at the University of Southampton.